Recently, scientists found that there is at least one in five teenagers hasve hearing loss. Recently, scientists found that at least one in five teenagers have hearing loss.

It is clearer

Recently, scientists have found that there is at least one in five teenagers hasve hearing loss. Recently, scientists have found that at least one in five teenagers have hearing loss.

Recently,scientists found that there is at least one in five teenagers has hearing loss. Recently,scientists found that at least one in five teenagers has hearing loss.

Recently, scientists found that there is at least one in five teenagers has hearing loss. Recently, scientists found that at least one in five teenagers has hearing loss.

Recently, scientists found that there is at least one in five teenagers who has hearing loss. Recently, scientists found that there is at least one in five teenagers who has hearing loss.

And hearing loss among young people has been grow upon the rise since 1990. And hearing loss among young people has been on the rise since 1990.

And hearing loss among young people has been grow upn since 1990. And hearing loss among young people has grown since 1990.

And hearing loss among young people (has been grow uping / has grown) since 1990. And hearing loss among young people (has been growing / has grown) since 1990.

You could also use the idiom "had been on the rise".

And hHearing loss among young people has been grow upon the rise since 1990. Hearing loss among young people has been on the rise since 1990.

The doctors guess that it might be because of the popularity of electronic devices among teenagers, such as MP3 phones, computers……, etc. What might doctors say about this? The doctors guess that it might be because of the popularity of electronic devices among teenagers, such as MP3 phones, computers, etc. What might doctors say about this?

Use "etc" at the end of a list to clearly suggest there are more reasons you haven't listed.

The doctors sugguesst that might be because of the popularity of electronic devices among teenagers, such as MP3 players, phones, computers……, etc. What might doctors say to teens about this? The doctors suggest that might be because of the popularity of electronic devices among teenagers, such as MP3 players, phones, computers, etc. What might doctors say to teens about this?

guess → suggest: This sounds more formal.

The doctors guess that it might because due to the popularity of electronic devices among teenagers, such as MP3 phones, computers…… What might, and so on. What could the doctors say about this? The doctors guess that it might be due to the popularity of electronic devices among teenagers, such as MP3 phones, computers, and so on. What could the doctors say about this?

The doctors sugguesst that it might be because of the popularity of electronic devices among teenagers, such as MP3 players, phones, computers……, etc. What might doctors say about this? The doctors suggest that it might be because of the popularity of electronic devices among teenagers, such as MP3 players, phones, computers, etc. What might doctors say about this?

The doctors guess that might because the popularity of electronic devices among teenagers, such as MP3 phones, computers…… etc... What might doctors say about this? The doctors guess that might because the popularity of electronic devices among teenagers, such as MP3 phones, computers etc... What might doctors say about this?

They might give someoffer advice about hearing careloss to teenagers. They might offer advice about hearing loss to teenagers.

"Hearing care" isn't a phrase that you would normally here. Just use "hearing loss" here instead. It would sound more natural.

They mightcould give some advice about hearing care to teenagers. They could give some advice about hearing care to teenagers.

They might give some advice about hearing care to teenageroffer advice to teenagers on how to prevent hearing loss. They might offer advice to teenagers on how to prevent hearing loss.

Like: use fewer headphones less, do more outsidedoor sports, or wearing a hearing aid. Like: use headphones less, do more outdoor sports, or wear a hearing aid.

It would be more natural to say "use headphones less" and "outdoor sports."

Like: use fewer headphonesFor instance, use headphones less often, do more outside sports, or wearing a hearing aid. For instance, use headphones less often, do more outside sports, or wear a hearing aid.

Using "Like:" is incorrect word order in English. You can write, "For (instance/example), activities like using headphones less often, doing more outside sports or wearing a hearing aid." too.

Like: use fewerFor example, use headphones less, do more outside sports, or wearing a hearing aid. For example, use headphones less, do more outside sports, or wearing a hearing aid.

Colons have to be used at the end of a complete statement to introduce a list.

Like: use fewerFor example, use headphones less, do more outsidedoor sports, or wearing a hearing aid. For example, use headphones less, do more outdoor sports, or wear a hearing aid.

Like: use fewer headphones, do, don't use headphones frequently, play more outside sports, or wearing hearing aids. Like, don't use headphones frequently, play more outside sports, or wearing hearing aids.